Makindo Medical Notes

Related Subjects: |Cellulitis |Pyoderma gangrenosum |Pemphigus Vulgaris |Toxic Epidermal Necrolysis |Stevens-Johnson Syndrome |Necrotising fasciitis |Gas Gangrene (Clostridium perfringens) |Purpura Fulminans |Severe burns |Anatomy of Skin |Skin Pathology and Lesions |Skin, Soft Tissue & Bone Infections

⚠️ Toxic Epidermal Necrolysis (TEN) is a rare, life-threatening dermatological emergency. It lies at the most severe end of the SJS–TEN spectrum, caused by an immune-mediated reaction against keratinocyte adhesion molecules. This leads to widespread skin necrosis, epidermal detachment, and mucosal involvement.

📌 About

• Part of the SJS–TEN spectrum (SJS: <10% BSA, TEN: >30% BSA, overlap: 10–30%).
• Marked by extensive epidermal sloughing, like a severe burn injury.
• High risk of sepsis, fluid loss, multi-organ failure, and death.

🧾 Aetiology

• 💊 Drug-induced (most common) – sulphonamides, cephalosporins, anticonvulsants (carbamazepine, phenytoin, lamotrigine).
• 🧬 Idiopathic cases → worse prognosis, esp. in haematological malignancy (e.g. leukaemia, lymphoma).
• 🦠 Higher risk in viral infections (notably HIV).
• 🧪 Genetic risk: slow acetylator phenotype predisposes.

💊 Common Culprit Drugs (≈50% cases)

• Allopurinol
• Carbamazepine / Lamotrigine
• Nevirapine
• Oxicam NSAIDs
• Phenobarbital
• Phenytoin
• Sulphonamides (e.g. sulfamethoxazole)
• Sulfasalazine

🤒 Clinical Features

• Prodrome: fever, malaise, myalgia (flu-like).
• Painful, rapidly spreading erythema → confluent blistering.
• Mucous membrane involvement: oral, ocular, genital.
• Widespread epidermal detachment → erosions, fluid loss, risk of infection.
• Sepsis & multi-organ failure are leading causes of death.

🔍 Differential Diagnosis

• Staphylococcal scalded skin syndrome (SSSS) – mucosa spared.
• Toxic shock syndrome.
• DRESS (Drug Reaction with Eosinophilia & Systemic Symptoms).
• Severe phototoxic reactions.

📊 SCORTEN Severity Score

• Age >40 years → +1
• HR >120 bpm → +1
• Underlying malignancy → +1
• BSA detachment >10% → +1
• Urea >10 mmol/L → +1
• HCO₃⁻ <20 mmol/L → +1
• Glucose >14 mmol/L → +1

💀 Mortality by SCORTEN

• 0–1 → ~3%
• 2 → ~12%
• 3 → ~35%
• 4 → ~58%
• ≥5 → ~90%

🧪 Investigations

• Bloods: FBC, U&E, LFTs, CRP, coagulation profile.
• Skin biopsy → differentiates TEN from SSSS.
• Blood & urine cultures; CXR if febrile.

🏥 Management

• 🔺 Admit ICU / burns unit if SCORTEN ≥2 or BSA >10% involved.
• ⚡ Supportive care: fluid/electrolyte balance, nutrition, thermoregulation.
• 🔥 Fire risk: paraffin-based emollients are flammable → CO₂ extinguisher + fire blanket at bedside.
• 🫁 Airway: anticipate obstruction if mucosa involved; use non-adhesive fixation.
• 💨 Breathing: monitor for ARDS; use lung-protective ventilation if intubated.
• 💉 Circulation: invasive access via unaffected skin; fluids, albumin, vasopressors as required.
• 🩸 Transfusion: maintain Hb >70 g/L (or >90 in CVD); monitor coagulopathy.
• 💊 Analgesia: opioids ± sedation for dressing changes; early pain team input.
• 🌡️ Exposure: prevent hypothermia (room 25–28°C; warmed IV fluids).
• 🥗 Nutrition: NG feeding early; consider parenteral if needed; beware refeeding syndrome.
• 🦠 Infection: barrier nursing; treat only proven infection (early Staph → later Gram-negatives like Pseudomonas).
• 👁️ Ophthalmology: daily review; lubricants ± topical antibiotics.

📚 References

• British Association of Dermatologists Guidelines
• NHS TEN Guidelines

🖼️ Images